Do NAD levels really decline as we age?
Nicotinamide adenine dinucleotide (NAD) is an essential coenzyme involved in processes such as cellular energy production, redox reactions, and the response to DNA damage. In recent years, the view that NAD levels decline with age and that this decline is one of the primary causes of aging has become widespread. However, human research published in the journal Nature Metabolism on November 4, 2026 shows that this narrative needs to be interpreted more carefully.
How was the study conducted?
In the cross-sectional study titled “Whole-blood NAD levels track cardiovascular disease but not chronological age,” a total of 1.340 whole-blood NAD measurements obtained from 1.068 adults were examined. Researchers evaluated the relationship of NAD levels with age, sex, and certain chronic diseases. This study is not an NAD supplement or IV therapy trial.
Study summary · November 4, 2026
It is a cross-sectional association study; it does not evaluate the treatment efficacy of NAD supplementation.
Key findings
- In healthy men, whole-blood NAD levels did not show a marked decline as chronological age advanced.
- In women, an association toward an increase with age was observed.
- Associations with lower NAD levels were reported in individuals with cardiovascular disease and hypertension.
These results do not support the claim that whole-blood NAD levels inevitably decline with age in every individual. Nevertheless, they do not rule out the possibility that age-related changes may occur in different tissues, cellular compartments, or NAD metabolites.
Does an NAD measurement show biological age?
A single whole-blood NAD result is not sufficient to determine a person’s biological age. The measurement method, distribution of blood cells, metabolic status, and accompanying diseases can affect the result. Furthermore, the fact that a biomarker is associated with a disease does not mean that raising that marker will prevent or treat the disease.
What does this mean in terms of NAD+, NMN, and NR supplements?
In some human studies conducted with NAD precursors, it has been shown that certain NAD metabolites increase. However, a biochemical increase is not the same outcome as an extension of lifespan, a reduction in cardiovascular events, or an improvement in clinical functions. This new study also did not test the clinical efficacy of NAD+, NMN, NR, or intravenous NAD administrations.
Our clinical approach
In a healthy aging assessment, rather than focusing on the level of a single molecule, it is more meaningful to consider cardiometabolic risks, sleep, physical capacity, muscle health, nutrition, and the person’s clinical history together. Although NAD metabolism continues to be an important area of research, clinical decisions should be grounded in individual-specific findings and results obtained from human studies.
Scientific source
Romenskaja-Avgul D et al. Whole-blood NAD levels track cardiovascular disease but not chronological age. Nature Metabolism. November 4, 2026. DOI: 10.1038/s42255-026-01660-3.
Disclaimer: This article was prepared for the purpose of explaining scientific research; it is not a personalized diagnosis or treatment recommendation.
